Abstract

Introduction
Chronic systemic inflammation plays an important role in the pathophysiology of a number of clinical diseases and conditions. Lifestyle modifications have been advocated for the treatment of chronic inflammation. Effects of diet and exercise on chronic inflammation have been summarized in several review articles. The purpose of this research letter is to review current evidence of potential effects of a popular mind–body exercise, t'ai chi, on chronic inflammation and to provide guidance for future research.
Methods
A literature search was performed using PubMed, Web of Science, and PsycINFO. The keywords were t'ai chi OR Tai Ji AND inflammation OR C-reactive protein OR cytokine OR interleukin 6 OR tumor necrosis factor α. Inclusion criteria were randomized controlled studies or quasiexperimental studies; written in English; middle-aged or older adults as sample participants. The literature search was conducted from inception to April 3, 2019.
The authors reviewed 175 articles and then assessed 26 articles for eligibility. Among 26 articles, 13 articles met the inclusion criteria. 1 –13 There were two sets of articles that describe the same studies. 3,4,7,8 The authors combined the two articles for one study, 3,4 and included one article for the other study. 8 Among the 11 studies, 9 studies were randomized controlled studies 1 –6,8–11 and 2 studies were quasiexperimental studies. 12,13
Results
Current randomized controlled studies on t'ai chi and chronic inflammation are summarized in Table 1. 1 –6,8 –11 Among these 9 studies, 3 were conducted in middle-aged or older cancer survivors, 3,4,6,9 4 studies were conducted in other subgroups of older adults (healthy older adults, and older adults with insomnia, depression, or mild cognitive impairment), 2,5,8,11 1 study was conducted in HIV-infected adults, 1 and 1 study was conducted in women with elevated cardiovascular disease risk. 10 All studies, except for 1, 10 included an active control group that received health education, cognitive behavioral therapy, or other interventions. The terms ranged from 3 weeks to 6 months, and the doses varied as the duration ranged from 1 to 2 h and the frequency ranged from one time per week to three times per week.
Effects of T'ai Chi on Chronic Inflammation: Current Randomized Controlled Studies
Significant and marginal differences.
Both groups received escitalopram (esCIT) 4 weeks before and during intervention.
CRP, C-reactive protein; GCSF, granulocyte colony stimulating factor; IFN, interferon; IL, interleukin; sICAM, soluble intercellular adhesion molecule; sIL-1RA, secretary interleukin-1 receptor agonist; sIL-6R, soluble IL-6 receptor; TNF, tumor necrosis factor.
Findings from these studies do not strongly support that short- to medium-term t'ai chi could reduce chronic inflammation in these special populations. Only one study indicated that compared with waitlist (nonactive) controls, 8 weeks of t'ai chi intervention lowered levels of proinflammatory cytokines in women with an elevated cardiovascular disease risk. 10 Three studies with active controls only showed a marginally significant effect of t'ai chi in lowering circulating levels of inflammatory markers and cytokines, 2,5,8 although the anti-inflammatory effect of t'ai chi was more significant at the cellular level as indicated by the decreased cytokine release levels by circulating mononuclear cells. 6,8 Six studies with active controls did not show a significant effect of t'ai chi on circulating levels of inflammatory markers and cytokines. 1,3,4,6,9,11
Two quasiexperimental studies were conducted by the same research group. 12,13 Compared with noncontact controls, 6-month t'ai chi practice did not alter circulating levels of inflammatory markers in older adults with periodontal disease, 12 and only lowered levels of one, but not other proinflammatory cytokines in older adults with metabolic disease. 13 These findings are consistent with those from the randomized controlled studies.
Discussion
Current randomized controlled studies do not support a definite anti-inflammatory effect of t'ai chi in various special populations. The effectiveness of t'ai chi intervention is likely influenced by the baseline levels of inflammatory markers/cytokines, and the components, intensity, duration, and term of the t'ai chi program. Specifically, the forms/movements of the t'ai chi program varied, so it is difficult to evaluate the “doses” of the cognitive inputs and physical movements of these t'ai chi programs. Also, most t'ai chi programs were designed to last for <6 months, and it is unlikely to see changes in inflammatory markers over a relatively short-term lifestyle intervention. Future longer-term intervention studies are needed to identify a definite effect of t'ai chi on systemic and cellular levels of inflammation, and its role in the prevention and treatment of clinical diseases and conditions.
Footnotes
Acknowledgment
None declared.
Author Disclosure Statement
No competing financial interests exist.
